1. Field of the Invention
The present invention relates to a photosensitive composition capable of changing its properties by undergoing a reaction upon irradiation with actinic rays or radiation, a compound for use in the photosensitive composition, and a pattern forming method using the photosensitive composition. More specifically, the present invention relates to a photosensitive composition for use in the production process of a semiconductor such as IC, in the production of a circuit substrate of liquid crystal, thermal head and the like, in other photofabrication processes or in the lithographic printing plate or acid-curable composition, and also relates to a compound for use in the photosensitive composition and a pattern forming method using the photosensitive composition.
2. Background Art
The chemical amplification resist composition is a pattern forming material capable of forming a pattern on a substrate by producing an acid in the exposed area upon irradiation with actinic rays or radiation such as far ultraviolet light and through a reaction using this acid as the catalyst, causing the area irradiated with actinic rays or radiation and the area not irradiated therewith to change in the solubility in a developer.
In the case of using a KrF excimer laser as the exposure light source, a resin having small absorption in the region of 248 nm and having a basic skeleton of poly(hydroxystyrene) is primarily used as the main component and this is an excellent system capable of forming a good pattern with high sensitivity and high resolution as compared with conventional naphthoquinonediazide/novolak resin systems.
In the case of using a light source of emitting light at wavelengths shorter than that, for example, in using an ArF excimer laser (193 nm) as the light source, a satisfactory pattern cannot be formed even by the above-described chemical amplification system because the compound having an aromatic group substantially has large absorption in the region of 193 nm.
In order to solve this problem, a resist containing a resin having an alicyclic hydrocarbon structure with high transparency has been developed for use with an ArF excimer laser. However, the alicyclic structure generally has low polarity, and the reactivity for deprotection in the resin is greatly decreased as compared with that in poly(hydroxystyrene). Therefore, an acid having high acidity is necessary for the image formation and a specific organic sulfonic acid is used, for example, in Patent Document 1 (JP-A-2002-131897 (the term “JP-A” as used herein means an “unexamined published Japanese patent application”)), Patent Document 2 (JP-A-2003-149812), Patent Document 3 (JP-T-11-501909 (the term (the term “JP-T” as used herein means a “published Japanese translation of a PCT patent application”)), Patent Document 4 (JP-A-6-242606), Patent Document 5 (JP-A-11-160861) and Patent Document 6 (U.S. Patent Application 2004/0087690A1).
However, many points still remain unsatisfied, and more improvement is demanded with respect to the exposure latitude, pitch dependency and line edge roughness as well as sensitivity and dissolution contrast at the exposure with EUV light.